A neutron star can form in the aftermath of the gravitational collapse of a massive star during a supernova. The name supernova remnant is applied to the phenomenon of the shock wave that results from the star's gravitational collapse; the shock wave expanding at a rate of 30,000 km/s and the consequent sweeping up of everything in its path (Schawinski et al, 2008). Supernova events are categorized, and a neutron star formation can occur during Type II, Type Ib, or Type Ic supernovas. In the aftermath of this gigantic and fast moving dust cloud there remains a star composed almost entirely of neutrons. Neutrons, having neutral electrical charge, are nearly the same mass as protons. That being said, neutron stars are incredibly dense and hot, though not particularly large. An average neutron star may be 1.35x-2.1x solar masses, but its radius may be a mere 12 km. That is 2.6×1014 to 4.1×1014 times the density of the sun!
A neutron star's compactness and high density means that it have very high levels of gravity on the surface. The escape velocity on a typical neutron star may be as high as 100,000 kilometers per second, nearly one third the speed of light. This means that anything that gets close enough to it will be accelerated toward the surface as a very high rate of acceleration, likely smashing that object back into, as Carl Sagan would say, 'star stuff.'
When the interior of a large star undergoes compression during a supernova, angular momentum of the particles is retained. Over time, the rotational inertia of the neutron star decreases, and common rotational periods range from 0.014 seconds to 30 seconds. For this reason, many astronomers throughout history have mistaken the predictable and quick rate of rotation for an intelligent source.
With regard to the formation of a neutron star, the class of supernova event preceding it will have implications for what to expect in th...